In a TDD wireless communication system that distinguishes transmission from reception by time-division of the same frequency, a Transmit/Receive Antenna Switch (TRAS) for switching between a high-power Radio Frequency (RF) transmission signal and a low-power RF reception signal protects a Low Noise Amplifier (LNA) at a receiver by blocking transmit power from the LNA in transmission mode and reduces noise introduced from a transmitter in reception mode. To implement the TRAS function, an RF switch is usually used, of which the switching is controlled based on a TDD synchronization signal. However, it may occur that the transmission/reception timing of the TDD synchronization signal is not identical to that of the RF transmission/reception signal in a BS. Then a downlink RF transmission signal whose power was amplified much may be introduced into the uplink reception path of a reception signal amplification/division module 70 and devices residing in the uplink reception path, such as an LNA may be damaged. To avoid this problem, an isolator is inserted at the output end of the LNA in hardware. However, if the isolator is damaged, the highly power-amplified downlink transmission RF signal may be introduced into the LNA, resulting in damage to the LNA.